Noise sustained waves in subexcitable media: From chemical waves to brain waves

Noise sustained waves in subexcitable media: From chemical waves to brain waves.

We discuss a novel type of spatiotemporal pattern that can be observed in subexcitable media when coupled to a thermal environment. These patterns have been recently observed in several different types of systems: a subexcitable photosensitive Belousov-Zhabotinsky reaction, hippocampal slices of rat brains, and astrocyte syncytium. In this paper, we introduce the basic concepts of subexcitable ...

Electric-field-sustained spiral waves in subexcitable media.

We present numerical evidence that, in the presence of a suitable electric field, an isolated broken plane wave retracting originally in subexcitable media can propagate continuously and eventually evolve into a rotating spiral. Simulations for the FitzHugh-Nagumo, the Barkley, and the Oregonator models are carried out and the same electric-field-sustained spiral phenomena are observed. Semiana...

Convection in chemical waves.

Brain Waves

Hans Berger (1873 – 1941) the German psychiatrist invented electroencephalography (EEG) for the recording of "brain waves" in 1924. He did this by measuring electrical activity in the brains of hospital patients with skull damage. He documented these alpha waves along with beta activity. He found that when alpha waves decrease and beta activity becomes dominant, we are fully awake. As he was th...

From Spiking Neurons to Brain Waves

Two models of the neocortex are developed to study normal and pathological neuronal activity. One model contains a detailed description of a neocortical microcolumn represented by 656 neurons, including superficial and deep pyramidal cells, four types of inhibitory neurons and realistic synaptic contacts. Simulations show that neurons of a given type exhibit similar behavior in this detailed mo...